Apparatus for the control of highway crossing signals



Jan. 1, 1946. s E. GILLESPIE 2,391,961

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed Jan. 28,1944 4] 45.5'- Y v H16' ATTORNEY Patented Jan. 1, 1946 UNITED STAT-ES*-PATENT OFFICE as'lgsef APATusFoi- THE QeN'rRn or' HIGHWAYCROSSINGISIGNALS Stainesr iEGillespieQ, Evanston,` Ill.; assig'nor 4toYy Western Railroad ySupply (elompanyfvr Chicago,

Ill., a corporation of Delaware Aplic'suohianuar'y 2s,1944,'sefiarNcn'520mg2V 3 Claims." (c1. 24a-4130 My invention relates toapparatus fior 'theff control of highway crossing' signals," andmoreVparticularly to control apparatus thatpr'ovides a substantially uniform`warning 'period of the fsigfnal vprior' to the arrivalof the train attheinter` 5 section regardlessof the speed'jof 'thetra'in A A highwaycrossing signal'is customarily con-"f trolled'th'rough an" approachor`operating'tr'ac'kf'r sefction which is of a length suiiic'ient to'provide l the signal prior to the arrival' of the train at theintersection when the-train is'traveling atthe maximum permissible speedforalltrains'.. l The" introduction `of high "speed trains has requiredthat such operating "section'bemincreased inflb" length, with theresultlthat the Vwarning period'` of the signal for a'slo'wltrainvmay'besolongasf tofbe annoying to 'the highway users. This'f condition has created fa demand' for' morduni-A A uniformtime controlcanbe 'accomplished'fbyf delaying thei'sta'rting of thel Warning'operation ofA the 'signal 'when' a slow train enters the operat" ingsection, `t h'e intervalA of delay'being fora duf ration which depends:upon'thesp'eed Ofhe train." Such `a time controlfrequire'sthat:thecontrer lapparatus includes; means a1-eng" the' itrackwayf'tofdetermine` the train speed, arid means t'o" clelay theVstartingofV thefwarnfing` Opf" eration 'of the highway crossing'signalfoilan' in-v "30 terval'made variable' according 'to' the speedfAccor,dingligr a 'feature of 'my inventionfis the" provision of novel:and improved uniforml time control apparatusjfor highway "crossingvsignals;y

Another feature Iof "myA invention is'th'e provi-V35'lr sion-' ofhighway' crossing signal control" appa# ratu's incorporating vnovel andimproved 'in'ea'n'sv by' which the speed Yof ay trainappro'aching: a l'highway" intersection isv determined and the" Warning operation of thehighway crossing sig'- 40 nal is delayed after such train reaches a"'iixed point for anv interval vthe"duration'of"which is variedaccording toj'the speed. Y

Still another Vfeature'of. mv invention 'is the? paratusin'corporatingnovel means ,toA introduce 'a preselected time interval at'the rstpartof the"t timejoccupancy of 'a` train-jin "a speed `Ameasuring sectionandtou'everse this Asequence 4in thetime occupancy of a trainsinail-'operating section.A

Again, a feature of my invention is Vthefprovii sion of novel motoroperating meahsfor ,moving a circuitecontactlactuating mem'Ber away'lrfrom'a i starting position ata uniformi-rate duringther` intervalconsumed by Aa vehicle intraveiihgff' Ithe sametor atadifferentf'uni'formrate, a contact being actuated byi'thi's memberduring va preseparatus embodyngmy invention Will appear as mthespeciiication progresses.I` y a .giver-'1, 'Warning period, usually "20jseconds; of iwi The foregoingfeaturesfadvantages and ob-f jects-'embodyingf'myfinvention' accomplish by formingthe track onthapproachside of the'interse'ction into consecutive track circuited'isecf'`ltions of preselected'lengthsfand byproviding a lmotor operated timemeasuring means which is governed'bythe's"e"track circuits to 'move aconfA tact' actuatingjjmember at'a uniform' rate :away

from* a Starting psitionduring the' time inter- Y iAuvailcor'igsuined"bya trainin traveling the most reformv time 'controlof highway crossing',signalsgfZo motejfandfjspeed measuring tracksectionand then reversing themoveme/ntof'the contact ac'- tuating'member'andrestoring it at a uniform rate back ',toitsj starting position ywhenVthe train enters the, secondi andV operating -track section.

AThis contactA actuatingl member isy made'to close a contactwh'enmoved'a predetermined distance j from its startingposition',k 'such distancerepre-V senting a timeintervalequalto the warning period prescribed forthe highway crossing signal, andwhichperiodis"usually taken as twentysecends;' {Ihefspeedimeasuring-section is made alengthequivalent'torthat'required to drive Vthe contact actuatingmemberjust short of the po-v sitionwhereothe contact is closed when thetrain is' traveling" atil the maximum --permissible speed.

Thusitheco'ritact "is not closed forl a train operat' 111': "aiiiheY'rjn,axirlrllirlrl,fsrid 'bui 1S Y Closed 'for an intervalforjaslowertraiinthe interval the contact is closed,beinginverselyproportional to the closedduningthereturn movement until thepredeterminedf position' of; fthe VContact `actuating memberisreaiecli'eifl;"and"v consequently, the inter-, i 1 Yalhe Wma??'mmSOSQdSubSequent "'00 ,the provision or highway crossing"signalcontrolar@l'45x t 'train' entering'the operating section is inversely contact" isinterposed in thecontrol circuit network'for the' highway'crossingsigna1,'"the ar` I IYrange'rient''beingr such'thatthe warning opera'. 50

tion of the signal isstartedfwhen "a train enters the' operating"se'ction'lunlesrs'the contact of the time measuring means' s'closed, andif such contact is closed, the warning period'i'sheld in abey-`:ancetuntil' such' tinieasthe` contactv is opened.

`It"fol1o'ws'that'f'or"a trainimoving at'themaximum speed, the warningoperation of the signal is started when a trainfenters the operatingsection, but that for a slower train the starting of the warningoperation of the signal is delayed for an interval, the duration of suchinterval being inversely proportional to the train speed.

The entrance end of the operating section is located from theintersection a 'distance equal tov The operating section may besubdivided'withv a third or positive operating section adjacent theintersection, and for which latter section the signal is operated evenif the train is not moving. This third or positive operating section Iconoci embodying my invention. Fig. 2 is a view taken on the line II-IIof the motor driven diierential beveled gear seil of the time measuringmeans of Fig. 1. Fig. 3 is a diagrammatic view showing a second form ofapparatus embodying my invention, and Fig. 4 is a view showing theconstruction of Vthe motor for the time measuring means of Fig. '3'.

In' each ofthe several views like reference characters are used todesignate similar parts.

Referring to Fig. 1, the reference characters la and Ib designate therails of a stretch of railway over which tramo normally moves in thepreferably make of a length suicient to provide the preselected warningoperation of the signal for a train moving at the minimum speed of thepreselected range of speeds for which a uniform operating period is tobe eiected. i Y

The time measuring 'means' preferably comprises two motors, adilierential beveled gear set and a drum having mounted on itsoutersurface contact actuating members. This drum is mounted on the cageportion of the diiierential beveled gear set. A Vrst one of the twomotors is connected to a first drive gearrof the set and the secondmotor is connected toa second drive gear of the set. The jtwo drivengears of the set are journaled in the drum. vEnergiz'ationV of the firstmotor with the second motor held stationary rotates the drum in onedirection, and energization of the second motor with the rst motorrheldstationary rotates the drum Lin the opposite direction. The rst motor isused to rotate the drum from a starting position toward an extremeposition which is a little less than one revolution, and the secondmotor is used to drive the drum from whatever position ithas advancedtowardV the extreme position back to the starting position. VBy usingdilerentgear ratios the rate at whichvthe drum is rotated in onedirection can be made differentvfrorn that'at which it is rotated in theother direction, and I prefr-V erably arrange the parts so that the drumis driven from the startinghposition toward the eXtreme position at arelatively fast rate .compared to the rate at which it is driven backtoward the starting position.V On the outer surface o'f'this drumareformed three cam segments each of which serves as a Vconta'c'tractuatingmember. One of these cam `segments is used to" close the contactinterposed in the control network for the highway crossing signal and itis formed so as to close the contacta preselected'number of degrees awayfrom the starting position and there`V after retain it closed. The othertwo cam'seg" ments are used to operate contacts interposed inthenm'o'tor operating circuits'so that the motor operating circuit forthe first motor is opened at the extreme position and the motor`Voperating circuit for the second'rm'otor is opened atv the startingposition. A checkcontact is preferably provided in the time measuringmeans to check its operating condition.

I shall describe two forms of apparatus embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic'view showing onelform of apparatus direction indicated by an arrow, and which railway isintersected by a highway H, a highway crossing signal S being located atthe intersection. Signal S may be any one of the standard forms ofhighway crossing signals, such as a barrier, agate, flashing lights or abell, or it may consist of a combination of such devices, and in Fig. 1,the signal S is shown as an audible signal in the form of an electricbell.

The rails' la and l b on the approach side of the intersection, that is,on the left-hand side as viewed in Fig. 1, are formed by insulated railjoints into three track sections D-E, E-F and F-G; and over which tracksections a train travels in the order named in approaching theintersection. As an aid in understanding the apparatus, I shall refer tosection Do-E as a speed measuring sec- A tion, section E--F as anoperating section and section F-G as a positive operating section. Thelengths of these track sections are made to agree with the maximumpermissible speed for all trains and with a preselected warning periodof the signal S prior to the arrival of a train at the intersection. Byway of illustration, I shall assume that the maximum permissible trainspeed is 120 miles per hour or 176 feet per second, and

a 20 second warning period of the highway crossing signal prior'to thearrival of the train at the intersection is required. I shall furtherassume that the warning period of 20 seconds is to be substantiallyuniform for all trains speeds between the maximum speed of miles perhour and a preselected minimum speed of 30 miles per hour or 44 feet persecond. YIt is to be understood of course that the invention is notlimited to such speeds and warning period, and other speed limits andwarning periods can be used. VUnder the circumstances herein assumed,the entrance end E of the operating section is made approximately 3520feet from the intersection, 3520 feet being the distance traveled by atrain moving at the maximum speed in the prescribed warning period (176x20) Preferably the section F-G adjacent the intersection is made ofY alength equal to that traveled by atrain moving at the prese-V lectedminimum speed in the 20 second warning period and in this instance thesection F-G is approximately 880 feet in length (44x20) The speedmeasuring sectionVD-E is of a length equal to that traveled by a trainmoving at thelmaximum speed in some preselected interval. Preferablythis selected interval is made relatively short so that the speedmeasuring section D-E as a battery 2 connected across the rails at one,f end of the section, and a relay designated vR'plus- 1 themotorsMI.and M2 are alike `and are constant', speed directY currentlnotors`supplied with .powerfrorn am7 Convenientsourcefofz ,direct current suchas a. batteryithe. terminals oftwhich are, indicated at Band C. Whiledirect .current motors are..shown,.it ,is -to beunderstood `thatconstant speed. alternating. current motors, such as'synchronous motors,may be used.

The dinerentialA beveled geai set :DG comprises four gears 4, 5, 6 and'Luears Sand l are driven `gears mounted .on shafts 8. and;- 9,respectively,

and which shafts are journaled in a drum DD. Gears 4 and 5 aredrivegears, gear. 4 being fixed -on ashaft `l I, journaled at .10, Aandgear 5 being xedpn ashat I la, journaled at iZ. Motor Ml is connectedfto`rshaft -ll through a motorshaft indicated. by adottedline VKi3 :and a.Wormgear 14, and .motor M2 is connected to -shaft Ha through a motorshaft 18., a geartrain i?, ashaft `I6 and worm gear i5. It is apparentthat .with

gear nheld stationary. and gear. 4.rotated,the -drivengears 6 Aand l.wlltravel around the gears 4 .and causing the drum-.DD to be rotated,and with gear 4 heldstationary and gear 5 rotated,

the two gears 6 and 1 `are also driven around .gears 4-and 5 causingdrum BD to ,be rotated.

Bypro.per. selection .ofy the. direction of operation of the motors,vthe drum .DD ,isfmadetd-rotate counterclockwise as viewed in Fig. 2when gear 4 issdrivenbymotor MIv andis lrotated clock- .Wise when.vgear. -is rotated through motor M2.

As. will appear hereinafter, the. drum .DD is. normallypositioned at astarting zornormal position, vand. is rotatable through a-movernentoi a'little less than one revolution to an extremepo- -sitionwhen gear 4. isthe driving -gearand drum ADD is rotated backeto thestartingposition-when gear 5 is -the driving gear. To -agree with theherein assumed lengths rof vthe track sections and with the hereinassumed warning period for signal S, the rate of rotation 'of drumv DDby gear 4 isy preferably twice the rate of rotation of the drum whendriven byv gear 5.

The outer surface of the'l drum DDw isrforrned ywith three cam segmentspositioned on the lines I a,y b and c,re spectivel y, andeach, of whichcam .segmentsserves as a contact actuating member.

For thesake of clarity, these threecam segments .19, .20..and ,2| areillustrated, in Fig. 1 .on separate circlesof thesurfaceof. the drunjrDD so, that their cooperation with associated contactscanbeclearlyshown. These contactfactuatingmembers v.and their .associatedcontactsgare shown in Fig. l at their respective positions forthestarting Vpo- .Sitiri ef. the. time. .measurina means. Theimction.of. .thesediierent contacts .arid contact. .actuating members. of .thetime. measuring .means --will .appear when theoreraton 0f the. apparatusis; described.

Control relay CR is. energized through. a cir- *cuitl networkcontrolledV by the track relays. ER .ami-.Fla and. the timet measuring`.means TM .as

will-appear shortly. Relay CR-in Vturndgoverns an obvious Loperatingmcircuit for l signal 1 S,Vv thisl circuit.v .being :.completed. lat.back l contactu '2 2 .of relay CR.

f. Normally, .that is,..when sections .D-.-E,. E-F and F-G areunoccupied, the .time-.measuring means. TM .is at its .startingposition., .lthat is, the position .shown sin. Ilig.V 1,. Vand .controlrelay- CR is--energized causing signal. S fto-be silent. rThe circuitpath .through .which relay CR is. normally energized can betracediromterminal Bthrough Afront contact '23..of.relay. ER,.fvront contactlu of-relayfFR .andwinding ofrelay CR. to. terminal C.

I shallnext `assume lthat a Vtrain travelingat ther-'maximum vspeed of.120 miles A.per hour- .approaches the-intersection, and which trainlupon ventering `.section .D-E shunts trackrelay ,D'Rsto complete acircuit. for motor. yMl .such motor .operating circuit extending from.terminal -B through,back-contactlvof relay DR, iront contact ZliofrelayER, a normally closed .contact 2l- 28. ofthe timemeasuring means,and ymotor Ml to terminal Cof the- .current source. .Motor Ml `isnowope-rateol todrive the lgear. 4.and.in turnto cause drum .DDI-toberotated .counterclockwise at a rate preselected .according to=the rateof roperation of motor .ML andthe proportioning `of the gears. -lt-is tobe observedthat as soon las the-.drum DD rotates .away fromfitsstarting-position, acontact 291-36 is closeddue tol camY segmentv 2Bmoving. out .ffromnnder .the -contactmember .29. .and allowing contact.member 29 to spring into engagement ,withcontact member. It has. beenassumedfor. illustration that. section D-..E is 1760 feet inlength,.and..thus this train mov-ing .at the-maXiInum.speed,.wouldtravel` the section .in substantially 10. ,.seconds. The parts. ofthetime measuring. means TM are `proportioned so. that ,ten seconds..oper,ation. of motor MI yrotates-drumDD just shortof thepoint lWhere`theccam segment l2|I reaches. a. contact member 3| to-raise contactmember 31.into contact with acontactmember 32.closing the circuittherethrough.

Nihenithistrain enters section E-rF, track .revlay ER is shuntedvto openiront contacts 23, .26 and-38, .and close vback contact :33. vTheopening of front contact 26 opens theci-rcuit for motor=Ml 'and .that.motor is. deenergized andthe counter- 4rclockwise rotation vof drum DDis stopped. ,The -closing of back contact 33 completes a vmotoroperating circuit for .motorM2,. suchcircuit extend- Aing fromterminaleB through .hack .Contact 33 of-relay ER, contact 29-30, ofthetimeA measuring means, and which Contact is now closed,.and

.motor .M2 to terminal C.` With motor.. M2 operated, the drum DD isrotated clockwiseback -to its starting position, at whichposition-thecontact 29-30 is opened and motor l.lVIZis-.deenergized, leaving thetime. measuring means,A atgits normal or starting position. Thevopeninguof front contact 23 ofrelay ER* .opens-the-circuit throughwhich the relay CR is normally energized and since there is no otherpath now. completed for relay CR, relay CR is releasedto. closeithe ingof the bell of signal S ceases.

ergized soV that when the rear end of the 'train passes over theintersection to vacate. section F-G, the relay CR is reenergized and thesound- I shall next assume that a train traveling at 60 miles per hourapproaches the intersection. This train upon entering section YD-Eshunts track relay DR and the motor operating circuit for motor Ml iscompleted so that the drum DD of the time measuring means is driven awayfrom the starting position the same as in the previous case. This trainconsumes approximately 20 seconds in passing through the speed measuringsection D-E and since, as explained hereinbefore, the contact 3I-32 isclosed Vten seconds from the starting position, the contact 3I32 isclosed during the last ten seconds of the operation of the drum inresponse to this train moving at 60 miles per hour. When this trainenters section E-F, track relayER is shunted to open the circuit formotor Ml, close the circuit for motor Y M2 and open one path of thecircuit network for relay CR, the same as explained for the previoustrain. Control relay CR is now supplied with current through a circuitpath that extends from terminal B through contact 34-35 closed in amanner to appear shortly, contact Sil-32 of the time measuring means andnow closed due to the position of drum DD, front contact 24 of relay FRand winding of relay CR to terminal C, and the sounding of the bell ofsignal S is delayed after this train enters the section E-F. Since motorM2, gear train Il and worm gear I5 are so proportioned that the drum DDis driven back toward its starting position at one-half the rate atwhichthe motor Ml drove the drum away from the starting position, contact3l-32, which was ,closed for the last ten seconds, of the' operation ofthe drum away from the starting position remains closed for the rst 20seconds of the operation of the drum by motor M2 before the contactsegment 2l is moved out from under the contact member 3| to allow thatcontact to spring out of engagement with contact member 32. That is tosay, the warning operation of signal S is delayed for an interval ofsubstantially 20 seconds subsequent to this train entering the sectionE-F. Since the point Eis 3520 feet from the intersection, and theoperation of signal S is delayed for 20 seconds after the train haspassed the point E, it follows that this train moving at 60 miles perhour has advanced to a point 1760 feet from the intersection before thebell is sounded and a 20 seconds warning period of the signal S iseffected.

Contact member 35 is attached through a linkage to a fly ball type ofgovernor 36 driven from a shaft 3l of the gear train Il. vThis linkageand governor are proportioned for contact member 35 to be moved downwardas viewed in Fig. 1 to vengage Contact 34 when motor M2 is operated atlrate to bring the drum DD back to a point where contact member 3i-3Z isopened at the proper time, thecircuit for relay CR is opened at con-:tact 34-35 to cause immediate operation of the signal S.

I shall next assume a train traveling at 30 miles an hour approaches theintersection. This train Vconsumes approximately 40 seconds in advancing4through the speed measuring section D-E, and contact 3|-32 is closedfor the last thirty seconds of this 40 seconds period of operation. WhenER,` the motor Ml is stopped and the motor M2 is operated as explainedhereinbefore. Also relay CR is retained energized through the circuitpath including contact 3|32. It requires substantially 60 seconds ofoperation of motor'MZ to drive drum DD back to the point where contact31-32 is open. In 60 seconds this train advances approximately 2640 feet(44x60) from the entrance end E of section E-F, and thus it has arrivedat the point F, which has been assumed to be 880 feet away from theintersection. That is to say, for a train moving at the minimumpreselected-speed of 30 miles per hour, the circuit for the relay CR isopened at contact 3|32 of the time measuring means, and at front contact24 of track relay FR at substantially the same moment. In any event the20 seconds warning period of the signal S is obtained for the trainmoving at the 30 mile per hour speed.

From the foregoing discussion it is apparent that the apparatus of Fig.1 operates to effect a substantially 20 seconds warning operation ofsignal S for any train speed between the maximum speed of 120 miles perhour, and the minimum preselected speed of 30 miles per hour.V

A train moving at a speed less than 30 miles per hour may consume inadvancing through section D--lly a time interval suihcient for motor MIto drive drum DD to its extreme position, Vand if so, cam segment I9raises contact member 21 to open contact 27-38 and deenergize motor Mistopping the movement of the drum at the extreme position. Under suchcircumstances, motor M2 would not likely be operated long enough torestore the drum to the point where contact 3I-32 is opened while thetrain is advancing through section E-F, and thus no operation of 'thesignal S would be eiTected for this train While it occupies section E-F.However, when any such slow moving train enters section F-G shuntingtrack relay FR to open front contact 24, the control circuit for relayCR is opened and relay CR releases to initiate the operation of signal Sirrespective of the position of the time measuring means. The operatingperiod of signal S in this case would be somewhat longer than the usual20 seconds, but since section F-G is relatively short, the train isvisible tothe highway users so that they can judge when it is safe topass over the intersection. Y

It is to be pointed out that in case the drum DD has not been fullyrestored to its starting position before a train has vacated sectionE-F, an alternative motor operating circuit is completed at frontcontact 38 of relay ER and front contact 39 of relay DR andmotorV M2 isenergized until the time measuring means is restored to its startingposition. This last mentioned motor circuit is also effective to resetthe time measuring means in case a train should enter the speedmeasuring section D-E and then reverse its direction an back out ofsection D-E. From the foregoing description of the operation of theapparatus of Fig. l, it is to be seen that the time measuring means isoperable to determine the speed of the train and having determined thetrain speed to so delay the'starting of the warning operation'of signalS that a substantiallyuniform warning period obtains for all trainspeeds between the permissible maximum speed and the preselected minimumspeed. In other words, the time measuring means is operable to interposea preselected time interval which corresponds to the desired warningperiod of the highway cross- -this train enters section E-F to shunttrack relay ing signal at the start in the time occupancy of atrainziin; the` vspeed :measuring .se ction; and. to re. verse athis:sequencefin athe. timey .occupancy of `the operating. sectionReferringto.. Fig. s 3,2ithe *apparatus*- isV substantiallythesamenas-.inFig 1, exceptior. thetime measuring..means, and adescriptionofthe. time measuringmeansfronly .or` Fig.. "3 is= requirect. In Fig@3,the time'. measuring means TMI comprises two rmotors M3C .and.Mllgficlifferentialz beveled gear set DG'. Zand: drumDD Theconstructionof- .the beveled gear. set DG. and drum DD. with itsV .contact"actuating .membersisthe. same as that of the time. measuring means.ofFi'g. l, and` thisy much of the time measuring'means of Fig. 3 neednotbe again described;

The motors :M3 'Sand.M4 arealikey and :adescription or one. is:suflloient. for both: These motors 'n aree' of *the .alternatinglcurrent.` vibrating polarized-.armature type; Referring tomotor M3 andlooking :at Figs. 13 'fandf 4,' two magnetizable cores v4Iandf42terminate 'in polepie'ces 43 and 44,1'respectively; and have theirother` ends joined bya magnetizablexbackstrap '.V A permanent magnet46-Lhas .one .pole contact with-the backstrapland its opposite poleterminating .inv an enlargedpolepiecednotfishown) adjacent the polepieces^43and "441 ofthe electromagnet in the well-known: arrangement.-Aipolarized armature 41 'is' pivotally.mounted-lat A250' ini theenlarged polelfpiecefofv thefpermanent magnet,' and is yso 'f disposedthat its two. endsf are vadjacent the pole pieces v43land' t4,yrespectively.- Two'windings 48`l`and-49'are mounted on'the coresf4Iand42, respectively.` These -'two windings' 48.and -49=vare connectedtof add their magnetizing eiiects and ff when current flows in one'direction through the windings, the pole'flpiece-43'isr the north poleand the fpole piece-44fisthesouth pole, with the resuit? `armature Y 41pivoted in the permanent lmagnetf46 is attracted towardpole piece 43,and when' currentowsinf the opposite direction in the 4twowindings';pole piece v 43 isvthe south pole and pole piece-*441s thenorth pole andfarmature 41 4is caused to swing toward the polepiece 445-If an alternating vcurrent issupplied `to the windings 48 and "49,ythe'armature 41 is attracted towardfthe'pole piece 43 each positive halfcycle of the current, and is attracted towardr -thepole piece 44'each'fnegative Vhalf cycle ofthecurrent.

InJ otherfwords, armature 41 vibrates ata rate corresponding tof-thefrequency of the Aalternatingccurreni..j

Alratchet Dawl 5I -is` pivoted-in a bracket member '52 secured -'to'armature 41, bracket lmember 52 extendingto oney side of the-armatureforl ratchet'pawl 45I toA operatively engage the'teeth of a ratchetwheel 53 Which-is'mountedl on a shaft`54'to brin-g wheel 53 in a planeparallel to the cores 4I and 42. A retaining pawl 55 is mounted tocooperate with ratchet wheel 53 to permit only clockwise rotation asviewed in Fig. 4.- of the wheel, such rotation being effected throughthe driving pawl 5I when operated due to the vibration of armature 41.

It is to be seen therefore that ratchet wheel 53 is advanced one tootheach swing of arma-- ture 41 so that the number of teeth the ratchetwheel is advanced each second corresponds to the frequency of thealternating current supplied to windings 43 and 49. The frequency of thealternating current used can be any suitable frequency within limits andsuch structure permits the use of alternating current of the commercialfrequency of cycles per second.

A pinion 5S is keyed to shaft 54 and meshes with agear.51;fwhichiskeyedto shaft I3 ,on which` the wormwheel otthe wormgear .I4 is secured. Consequentlywhen alternating cur--V rent isSuppliedto windings 43 and 49-of motor M3the gear 4 of thefdiierentialgear set is driven at a lsubstantially uniform rate, Ythis rate beingpredetermined according to the frequency ofthe currentrand by theproportioning of the parts ofthe gears and theratchet wheel.

Motor M4' -is o similar construction and drives a ratchet wheel 5B;keyed to a shaft' 59 on which is secured a piniont 'meshingwith a gear6I; keyed to the shaft Ilwhich-carriesthe worm wheel of worrngear I5.ThusmotorM4 -isoperable-to drive the` gear -5 vof :the ydiilerentialgear set ata rate predetermined -by the frequencyof thealternatingcurrent and Icy-fthe proportioning of thegears and ratchetwheel.y

It is readily -to be seen therefore that V`,the drum DD of-thetimemeasuring .means -TMI- can be made to rotate iromits `starting pointtoward; its f extreme position at a'. predeterminedrate,bytheenergizationoI motor.M3, and can be made to rotate towarditsstarting -position either at the same or at a ydiierent predeterminedrate throughthe energization oi motor M4.

Motors M3 and 'M4 are provided Awith oper-- ating circuits whichcorrespond tothe. motor operating circuits for motors MI andMZ',respectively; of Fig. l except to be supplied with ,alternating currentfrom: a sourcehavingterminals BX and CX. The time measuringqmeans TM-I-is thus operable to control the contactlh-32gy in response tovtrainsoperating in sections D--E` and E-F' in substantially the kksame manner-as the contact is governed by the time Vmeasuringmeans In Fig. 3,-'thecontact 3I-.-32 ;of` thetime mease` uring meansis. used to control :analternating current relay CRI, a; front contact 62 of; which is includedYin the by-pass controLcircuit for the signal controlrelay CR. In thisway-thepresence of. the alternating current power .used to energizemotors M3 vand MIL-is checked,vand aloss of such power removes the timemeasuring means TMI from delaying the operation of the highway crossingsignals, signalY S` being then controlled through. thev track relays ERand FRY.

They operation of the apparatus of Fig.; 3 todo termine vthe speed of atrain and to controlA the startingof the warning operation of signal Sso that a substantially uniform warning period obtains for al1 trainspeeds between the permissible maximum speed and the preselectedmin-ivmum speed'will be apparent from an inspection of Fig. 3 taken inconnection with the description-of the operation of 'therapparatus-ofFig. 1. Apparatushere disclosed has the advantages that the vtime.measuringmeans 4is simple Ainconfstruction, reliable in its operationand can readily be adjusted as to gear ratio and speed of operation, sothat the apparatus can be applied and made to agree with the train speedprevailing at the specific location at which it is used. Also, acommercial source of power may be used.A

Although I have herein shown and described only two forms of apparatusfor the control of highway crossing signals embodying my invention, itis understoodthat various changes and modications may be made thereinwithin .the scope of the appended claims without departing from thespirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In time measuring means for highway crossing signal control apparatusgoverned by a train for operating the signal a substantially uniformtime period for all train speeds between preselected maximum and minimumspeeds, the combination comprising,Y a drum mounted to be rotated apreselected portion of a revolution :between a starting and an extremeposition a first,

' a second and aV third contact actuating' member formed on said drum toactuate a first, a second and a third contact respectively; said rstcontact `to be opened only at said extreme position, said second contactto be opened only at said starting position, said third contact to beclosed at a preselected point away from said starting position andthereafter retained closed to the eX- treme position, a differentialbevel gear set having a driven gear mounted on a shaft disposed at rightangles to the axis of the drum and secured in said drum to rotate thedrum, a rst motor connected to a first driving gear of said gear set andoperable'when energized to rotate said drum from the starting positiontoward said extreme position at a predetermined rate, a second motorconnected toa second driving gear of said gear set and operable whenenergized vto rotate the drum from the extreme position toward thestarting position at a predetermined rate, said rst contact included inan energizing circuit for said first motor, said second contact includedin an energizing circuit for said second motor, and said third contactincluded in a highway crossing signal control circuit.

2. In time measuring means for highway crossing signal control apparatusgoverned by a train for operating the signal a substantially uniformtime period for all train speeds between preselected maximum and minimumspeeds, the combination comprising, a drum mounted to be rotated apreselected portion of a revolution between a starting and an extremeposition; a first, a second and a third contact actuating member formedon saiddrum'to actuate a rst, a secondand a third contact respectively;said rst contact to be opened only at said extreme position, said secndcontact to be opened only at said starting position, said third contactto be closed at a preselected point away from saidv starting positionand thereafter retained closed4 to vthe extreme position, a differentialbevel gear set having a driven gear mounted on a shaft disposed4 atright angles to the axis of the drum and secured in said drum to rotatethe drum, a first and a second motor means, each of Vsaid motor meansincluding an alternating current magnet having a vibrating armature onwhich is carried a pawl that engages a ratchet wheel to rotate suchwheel at a rate predetermined by the frequency of the alternatingcurrent, the ratchet wheel of said iirst motor means connected to a rstdriving gear of said gear set to rotate said drum from the startingposition toward said extreme position at a predetermined rate when thatmotor means is energized, the ratchet wheel of said second motor meansconnected to a second driving gear of said gear set to rotate said drumfrom the extreme position toward the starting position at apredetermined rate when that motor means is energized, said iirstcontact in cluded in an energizing circuit for said first motor means,said second contact included in an energizing circuit for said secondmotor means and said third contact included in a highway crossing signalcontrol circuit. Y

3. In combination, a stretch of railway intersected by a highway andformed with a measuring and an operating track circuited section, a

highway crossing signal at said intersection', aY

differential bevel gear set having arst and a second driving gearsecured to a first and a second shaft respectively and a driven gearmounted on a thirdshaft and meshing with both of said driving gears,said rst and second shaft in alignment, a drum mounted with its axiscoinciding with the axis of said first and second shafts and having saidthird shaft secured therein, a first and a second contact actuatingmember formed on said drum to actuate a first and a second contactrespectively, a first motor connected to said first shaft and operablewhen energized vto rotate said drum in a first direction at apredetermined rate, a second motor connected to said second shaft andoperable when energized to rotate the drum opposite to said firstdirection at a predetermined rate, a rst circuit including a contact ofthe track relay of the measuring section and said lirst contact toenergize said first motor, a second circuit including a contact of thetrack relay of the operating section and said second contact Vtoenergize said second motor,'said first and second contacts disposed withrespect to said rst and second contact actuating members for said lirstmotor to rotate the drum from a rst position toward a second positionuntil said second position which is less than one revolution is reachedto measure the time consumed by a train in traveling the measuringsection and for said second motor to rotate the drum back to the firstposition when the train enters the operating section, a third contactactuating member formed on the drum to operate a third contact at apreselected point between lsaid first and secondpositions, and a controlcircuit for said signal having one branch including a contact of thetrack relay of the operating section and a second branch including saidthird contact.

STANLEY E. GILLESPIE.

